How do a bunch of cables and electricity make a computer?

Ok, so I'm helping my friend build a PC, and I thought to myself, how do these bunch of wires and whatnot make such an advanced device? Let's not even mention the fact that you can communicate with others simply using internet, which, I also cant make sense of how it exists. When I open a device, I see a bunch of squares and wires, and I'm awfully sure the squares are full of more wires, but it all somehow creates all this fantastic technology (Which a lot of people take for granted and don't realize how important it is). So, if someone can please explain to me how it even makes sense that a bunch of wires make a computer (In a not-complicated manner), I would be thankful.